• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2006.06a
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• pp.75-78
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• 2006

GF(2)위에서 최대길이를 갖는 n-셀 90/150 셀룰라 오토마타의 각 셀은 길이가 $2^n-1$인 수열을 생성한다. 이러한 셀룰라 오토마타의 임의의 셀에 대한 출력수열은 다른 셀에 대한 출력수열의 위치를 이동함으로써 얻을 수 있다. 본 논문에서는 주어진 셀룰라 오토마타의 상태전이행렬의 특성다항식에 의한 동차 선형점화식을 만족하는 충격반응수열을 이용하여 셀들의 위상이동차를 계산하는 알고리즘을 제안한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.4
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• pp.3-10
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• 2005

Every cell position of a maximum-length 90/150 cellular automata(CA) generates the same pseudo-noise(PN) sequence corresponding to the characteristic polynomial of the CA with a phase shift. Unlike LFSRs, the phase shift is generally different between stages of a CA. In this paper, we propose an algorithm to compute relative phase shifts between stage of a CA. Our algorithm does not need Shank's algorithm to compute relative phase shifts and does not need any previous phase shifts to compute a phase shift. Moreover it is done in time $O(2^n)$.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.6
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• pp.25-30
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• 2004

Linear cellular automata(CA) which generate maximum-length cycles, have wide applications in generation of pseudo-random patterns, signature analysis, cryptography and error correcting codes etc. Linear CA whose characteristic polynomial is primitive has been studied. In this paper Ive propose a effective method for generation of a variety of maximum-length CA(MLCA). And we show that the complemented CA's derived from a linear MLCA are all MLCA. Also we analyze the Properties of complemented MLCA. And we prove that the number of n-cell MLCA is ${\phi}(2^{n}-1)2^{n+1}$/n.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.9
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• pp.1565-1572
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• 2006

Recently with the ever increasing growth of data communication, the need for security and privacy has become a necessity. The advent of wireless communication and other handheld devices like Personal Digital Assistants and smart cards have made the implementation of cryptosystems a major issue. The Cellular Automata(CA) can be programmed to implement hardware sharing between the encryption and decryption. In this paper, we give conditions for a linear hybrid cellular automata with 60, 102 or 204 to be a linear hybrid group cellular automata C. And we present the conditions which the complemented hybrid group cellular automata C' with complement vectors derived from C has maximum equal lengths in the state transition diagram of C' Also we analyze the relationship among cycles of C' These results generalize Mukhopadhyay's results.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.1071-1074
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• 2004

최대길이를 갖는 선형유한상태기계(LFSM)가 패턴생성, 신호분석, 암호, 오류정정 부호에 응용되면서 n차 원시다항식을 특성다항식으로 갖는 선형유한상태기계에 관한 연구가 활발하게 이루어지고 있다. 본 논문은 최대길이를 갖는 다양한 셀룰라 오토마타의 효과적인 생성방법을 제안한다. 특성다항식이 n 차 원시다항식인 선형 MLCA로부터 유도된 여원 CA가 MLCA임을 밝히며 여원 MLCA의 여러 가지 성질들을 분석한다. 또한 n-셀 MLCA를 ${\phi}(2^n-1)2^{n+1}/n$개 생성할 수 있음을 보인다.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2006.06a
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• pp.83-86
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• 2006

본 논문에서는 합성된 90/150 그룹 셀룰라 오토마타의 특성다항식을 분석하고 이러한 셀룰라 오토마타의 구조와 특성다항식의 관계를 살펴본다. 또한 최대길이를 갖는 그룹 셀룰라 오토마타로부터 유도된 여원 셀룰라 오토마타의 구조가 선형 셀룰라 오토마타와 동형임을 밝힌다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.5
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• pp.1201-1208
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• 2010

In this paper, we propose an image encryption method using two linear MLCA(Maximum Length Cellular Automata). The encryption method first sets arbitrary 8 bit initial values. Next, we create high quality PN(pseudo noise) sequences by converting rows and columns with the set initial values. hen we generate a basis image using the set PN sequences. Lastly, the final image with high encryption level is produced by XOR operation of the basis image and the original image. In order to verify that the proposed method has the high encryption level, we performed histogram and stability analysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.10
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• pp.2283-2291
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• 2010

The shrinking generator which is one of clock-controlled generator is a very simple generator with good cryptographic properties. A nonlinear sequence generator based on two 90/150 maximum length cellular automata can generate pseudorandom sequences at each cell of cellular automata whose characteristic polynomials are same. The nonlinear sequence generated by cellular automata has a larger period and a higher linear complexity than shrunken sequence generated by LFSRs. In this paper we analyze shrunken-interleaved sequence based on 90/150 maximum length cellular automata. We show that the sequence generated by nonlinear sequence generator based on cellular automata belongs to the class of interleaved sequence. And we give an effective algorithm for reconstructing unknown bits of output sequence based on intercepted keystream bits.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.393-396
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• 2006

In this paper, we analyze the characteristic polynomials of 90/150 cellular automata which uses only 90, 150 rules as state-transition rules. In particular, we propose the method which the characteristic polynomial is represented as the exponential type of a primitive polynomial by synthesizing 90/150 CA.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.5
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• pp.1001-1008
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• 2019

A high-quality pseudorandom sequence generation is an important part of many cryptographic applications, including encryption protocols. Therefore, a pseudorandom number generator (PRNG) is an essential element for generating key sequences in a cryptosystem. A PRNG must effectively generate a large, high-quality random data stream. It is well known that the bitstreams output by the CA-based PRNG are more random than the bitstreams output by the LFSR-based PRNG. In this paper, we prove that the complemented CA derived from 90/150 maximum length cellular automata(MLCA) is a MLCA to design a PRNG that can generate more secure bitstreams and extend the key space in a secret key cryptosystem. Also we give a method for calculating the cell positions outputting a nonlinear sequence with maximum period in complemented MLCA derived from a 90/150 MLCA and a complement vector.